Race Day Nutrition

Carbo Loading and Race Day Nutrition

Here are just some simple bullet point notes to give you a guide. Surf the net – there is a plethora of information out there but steer clear of the extreme stuff. The following is as recommended by the Australian Sports Commission [1] and Triathlon Australia.


  • Where event is over 90 minutes


  • Carbo loading increases stores of glycogen levels;
  • Improves endurance from between 2-3 %
  • You can only get a certain amount of carbs into the body per hour during a race

Should I Carb Deplete Before – Myth !

  • No. However, you should be well and truly be tapering off all exercise.

What and How Much

  • The carbo load should start 3-4 days before a big race.  For an Ironman this starts for me on the Wednesday car trip down to an Ironman.[2]
  • The precise amount of carbohydrates you are looking for is between 7-12gm carbohydrates per kilogram of body weight.
  • Probably lean toward high GI foods – white rice, pasta, corn and simple sugars found in softdrinks, some sports drinks
  • REDUCE – Fats and proteins and especially fibre (High fibre index = low GI index)

BBB – Personal Points

  • Expect to lose “body definition” – you are doing probably the reverse of what a body builder is doing pre-competition !
  • Headaches are a common feature of a hypernatremia. (Indicating perhaps a sodium imbalance – get in extra salt and/or an electrolyte like Nuun. Something with magnesium is good, but do not exceed recommended dosages)
  • I taper-off eating solids around noon Saturday converting to more liquid forms of carbs and little fibre
  • I also taper off hydration saturation about mid-afternoon as well. If you are not peeing clearly by this stage then…..
  • Last meal I have is a small portion of steak, some green fresh salad, a little pasta/rice (salty) with a good quantity of soda water. A mars bar before bed J

Race morning

  • Stick to how you have trained all year. For ironman distances don’t be afraid of feeling full – remember it will be around 1 ½ hours between consumption of any calories between mingling for swim start and getting to T1.
  • 2g of carbs per 1 kg of body weight > 2hrs before start
  • If you drink coffee – get a good strong one in (but expect to pee – don’t worry this is not dehydrating you if you are a habitual coffee drinker.) 3-6mg/ 1kg of body weight.

The Balance

  • You try to get in during each leg, the carbs you are going to need for the next leg. The cycle leg is the optimal time to be hydrating and carbing properly for a solid run
  • Before leaving T1 to go to swim start – get down last few carbs
  • Exiting T1 onto bike – take 10-30 mins (depending on length of course) to ease HR down and to get in at least 750mL of electrolyte (non-carb, isotonic)
  • For fluids, work on at least 750mL per 1hour. Increase if you are larger athlete or hot day.
  • Avoid swallowing gus with a hypotonic fluid
  • Here, the consumption rate should be 1g of carbs per 1kg of body weight. Or, 250-300 calories (1000-1200kJ) during the bike and 200-250 calories on the run.
  • SALT – At least 1 tablet an hour, up to 4 an hour if it is hot. [3]
  • CAFFEINE - Caffeine aids in the muscle utilization of glycogen (carbohydrate). But don’t overdo it. The AIS protocols recommend only 1-3 gm/ 1kg of body weight per hour.  There is no use loading more than this as it has no positive effect.

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*Ideally you will have tested the carbo loading and race day nutrition at a B priority race or during training to see what does/not work for you or causes stomach irritation.


[1] http://www.ausport.gov.au/ais/nutrition/factsheets/competition_and_training/carbohydrate_loading

[2] International racers should consider a travel diet / sleep plan from Travel Physio; http://www.rehabphysio.com.au/

[3] This assumes you have normal kidney function